runtime/JSNotAnObject.h

   1 /*
   2  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  14  *     its contributors may be used to endorse or promote products derived
  15  *     from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #ifndef JSNotAnObject_h
  30 #define JSNotAnObject_h
  31
  32 #include "JSObject.h"
  33
  34 namespace JSC {
  35
  36     class JSNotAnObjectErrorStub : public JSObject {
  37     public:
  38         JSNotAnObjectErrorStub(ExecState* exec, bool isNull)
  39             : JSObject(exec->globalData().notAnObjectErrorStubStructure)
  40             , m_isNull(isNull)
  41         {
  42         }
  43
  44         bool isNull() const { return m_isNull; }
  45
  46     private:
  47         virtual bool isNotAnObjectErrorStub() const { return true; }
  48
  49         bool m_isNull;
  50     };
  51
  52     // This unholy class is used to allow us to avoid multiple exception checks
  53     // in certain SquirrelFish bytecodes -- effectively it just silently consumes
  54     // any operations performed on the result of a failed toObject call.
  55     class JSNotAnObject : public JSObject {
  56     public:
  57         JSNotAnObject(ExecState* exec, JSNotAnObjectErrorStub* exception)
  58             : JSObject(exec->globalData().notAnObjectStructure)
  59             , m_exception(exception)
  60         {
  61         }
  62
  63         static PassRefPtr<Structure> createStructure(JSValue prototype)
  64         {
  65             return Structure::create(prototype, TypeInfo(ObjectType, StructureFlags), AnonymousSlotCount);
  66         }
  67
  68      private:
  69
  70         static const unsigned StructureFlags = OverridesGetOwnPropertySlot | OverridesMarkChildren | OverridesGetPropertyNames | JSObject::StructureFlags;
  71
  72         // JSValue methods
  73         virtual JSValue toPrimitive(ExecState*, PreferredPrimitiveType) const;
  74         virtual bool getPrimitiveNumber(ExecState*, double& number, JSValue&);
  75         virtual bool toBoolean(ExecState*) const;
  76         virtual double toNumber(ExecState*) const;
  77         virtual UString toString(ExecState*) const;
  78         virtual JSObject* toObject(ExecState*) const;
  79
  80         // Marking
  81         virtual void markChildren(MarkStack&);
  82
  83         // JSObject methods
  84         virtual bool getOwnPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
  85         virtual bool getOwnPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);
  86         virtual bool getOwnPropertyDescriptor(ExecState*, const Identifier&, PropertyDescriptor&);
  87
  88         virtual void put(ExecState*, const Identifier& propertyName, JSValue, PutPropertySlot&);
  89         virtual void put(ExecState*, unsigned propertyName, JSValue);
  90
  91         virtual bool deleteProperty(ExecState*, const Identifier& propertyName);
  92         virtual bool deleteProperty(ExecState*, unsigned propertyName);
  93
  94         virtual void getOwnPropertyNames(ExecState*, PropertyNameArray&, EnumerationMode mode = ExcludeDontEnumProperties);
  95
  96         JSNotAnObjectErrorStub* m_exception;
  97     };
  98
  99 } // namespace JSC
 100
 101 #endif // JSNotAnObject_h